From the Journals

Nonablative laser improved PIH in patients with darker skin



A low-density nonablative laser successfully treated postinflammatory hyperpigmentation (PIH) in a group of patients with darker skin types, Yoon‐Soo Cindy Bae, MD, and colleagues reported.

Among patients treated with the nonablative fractional 1,927 nm laser, there was a mean improvement of about 43% in hyperpigmented areas, and no side effects were reported, wrote Dr. Bae, of the department of dermatology at New York University and the Laser & Skin Surgery Center of New York, and coauthors in Lasers in Surgery and Medicine.

Lasers have not been the first choice for hyperpigmentation in Fitzpatrick skin types IV, V, and VI, they pointed out. More commonly used treatments are hydroquinone and chemical peels that use glycolic acid or salicylic acid. But these are not always ideal options, Dr. Bae said in an interview.

“There are side effects to medical therapy. The drawbacks of medical therapy include compliance issues, risk of skin irritation from the product ... and a risk of hyperpigmentation specifically for hydroquinone. There are also risks to laser therapy, including dyspigmentation and scarring,” she added. “However, the laser we used is a low energy, nonablative type of laser, so the risk of scarring is extremely rare and the dyspigmentation is actually what we are aiming to treat.”

The retrospective study comprised 61 patients with PIH who had received more than one treatment with the low energy fractionated 1,927 nm diode laser between 2013 and 2016. Most were Fitzpatrick type IV (73.8%). The remainder were Type V (16.4%) and Type VI (9.8%). The most common treatment site was the face or cheeks (68.9%), followed by legs (13%), the rest of the cases were unspecified.

Patients had received treatment with the laser with fixed fluence at 5 mJ, fixed spot size of 140 micrometers, depth of 170 micrometers, and 5% coverage. They required several treatments: 15 had two, 14 had three, 16 had four, and the remainder had five or more. Topical treatment data were not collected. Photographs taken before treatment and before the last treatment were evaluated by dermatologists who had not treated the patients. Based on those evaluations, the mean improvement was a statistically significant 43.2%.

There did not, however, appear to be much difference between the treatment groups. The mean improvement among patients with two treatments was 44.5%; three treatments, 44.29%; four treatments, 40.63%; five or more treatments, 43.75%.

Although those with darker skin types tended to have better results, there were no statistically significant differences between the skin-type groups. Among those with Fitzpatrick skin type IV, the mean improvement was 40.39%; skin type V, 47.25%; and skin type VI, 57.92%.

“The fact that there was no correlation between Fitzpatrick skin type … and average percent improvement demonstrates that this laser is a viable treatment option for patients with very dark skin,” the authors wrote. “There were also no significant differences between the average percent improvements for people receiving different numbers of treatments. A trend was observed that favored treating patients with darker skin type; however, this lacked statistical significance. This may have been due to an underpowered study.”

Limitations of the study included the retrospective design and nonstandardization of photographs; “further studies with prospective controlled designs are needed to confirm our findings,” they added.

No funding or disclosure information was provided.

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SOURCE: Bae YS et al. Lasers Surg Med. 2019 Oct 29. doi: 10.1002/lsm.23173.

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